sources.list should be a text file with a source file name in each line Filenames should be specified relative to the current directory, for example if you are in the build-scripts directory and want to create the testgles.c test, you'll run:

./androidbuild.sh org.libsdl.testgles ../test/testgles.c

One limitation of this script is that all sources provided will be aggregated into a single directory, thus all your source files should have a unique name.

Once the project is complete the script will tell you where the debug APK is located. If you want to create a signed release APK, you can use the project created by this utility to generate it.

Finally, a word of caution: re running androidbuild.sh wipes any changes you may have done in the build directory for the app!

For more complex projects, follow these instructions:

Copy the android-project directory wherever you want to keep your projects and rename it to the name of your project.

Move or symlink this SDL directory into the “/app/jni” directory

Edit “/app/jni/src/Android.mk” to include your source files

4a. If you want to use Android Studio, simply open your directory and start building.

4b. If you want to build manually, run ‘./gradlew installDebug’ in the project directory. This compiles the .java, creates an .apk with the native code embedded, and installs it on any connected Android device

Here's an explanation of the files in the Android project, so you can customize them:

android-project/app
build.gradle - build info including the application version and SDK
src/main/AndroidManifest.xml - package manifest. Among others, it contains the class name of the main Activity and the package name of the application.
jni/ - directory holding native code
jni/Application.mk - Application JNI settings, including target platform and STL library
jni/Android.mk - Android makefile that can call recursively the Android.mk files in all subdirectories
jni/SDL/ - (symlink to) directory holding the SDL library files
jni/SDL/Android.mk - Android makefile for creating the SDL shared library
jni/src/ - directory holding your C/C++ source
jni/src/Android.mk - Android makefile that you should customize to include your source code and any library references
src/main/assets/ - directory holding asset files for your application
src/main/res/ - directory holding resources for your application
src/main/res/mipmap-* - directories holding icons for different phone hardware
src/main/res/values/strings.xml - strings used in your application, including the application name
src/main/java/org/libsdl/app/SDLActivity.java - the Java class handling the initialization and binding to SDL. Be very careful changing this, as the SDL library relies on this implementation. You should instead subclass this for your application.

Any files you put in the “app/src/main/assets” directory of your project directory will get bundled into the application package and you can load them using the standard functions in SDL_rwops.h.

There are also a few Android specific functions that allow you to get other useful paths for saving and loading data:

SDL_AndroidGetInternalStoragePath()

SDL_AndroidGetExternalStorageState()

SDL_AndroidGetExternalStoragePath()

See SDL_system.h for more details on these functions.

The asset packaging system will, by default, compress certain file extensions. SDL includes two asset file access mechanisms, the preferred one is the so called “File Descriptor” method, which is faster and doesn't involve the Dalvik GC, but given this method does not work on compressed assets, there is also the “Input Stream” method, which is automatically used as a fall back by SDL. You may want to keep this fact in mind when building your APK, specially when large files are involved. For more information on which extensions get compressed by default and how to disable this behaviour, see for example:

If SDL_HINT_ANDROID_BLOCK_ON_PAUSE hint is set (the default), the event loop will block itself when the app is paused (ie, when the user returns to the main Android dashboard). Blocking is better in terms of battery use, and it allows your app to spring back to life instantaneously after resume (versus polling for a resume message).

Upon resume, SDL will attempt to restore the GL context automatically. In modern devices (Android 3.0 and up) this will most likely succeed and your app can continue to operate as it was.

However, there‘s a chance (on older hardware, or on systems under heavy load), where the GL context can not be restored. In that case you have to listen for a specific message, (which is not yet implemented!) and restore your textures manually or quit the app (which is actually the kind of behaviour you’ll see under iOS, if the OS can not restore your GL context it will just kill your app)

================================================================================ Threads and the Java VM

If you want to use threads in your SDL app, it‘s strongly recommended that you do so by creating them using SDL functions. This way, the required attach/detach handling is managed by SDL automagically. If you have threads created by other means and they make calls to SDL functions, make sure that you call Android_JNI_SetupThread() before doing anything else otherwise SDL will attach your thread automatically anyway (when you make an SDL call), but it’ll never detach it.

================================================================================ Using STL

You can use STL in your project by creating an Application.mk file in the jni folder and adding the following line:

The best (and slowest) way to debug memory issues on Android is valgrind. Valgrind has support for Android out of the box, just grab code using:

svn co svn://svn.valgrind.org/valgrind/trunk valgrind

... and follow the instructions in the file README.android to build it.

One thing I needed to do on Mac OS X was change the path to the toolchain, and add ranlib to the environment variables: export RANLIB=$NDKROOT/toolchains/arm-linux-androideabi-4.4.3/prebuilt/darwin-x86/bin/arm-linux-androideabi-ranlib

Once valgrind is built, you can create a wrapper script to launch your application with it, changing org.libsdl.app to your package identifier:

If the setprop command says “could not set property”, it's likely that your package name is too long and you should make it shorter by changing AndroidManifest.xml and the path to your class file in android-project/src

You can then launch your application normally and waaaaaaaiiittt for it. You can monitor the startup process with the logcat command above, and when it‘s done (or even while it’s running) you can grab the valgrind output file:

adb pull /sdcard/valgrind.log

When you're done instrumenting with valgrind, you can disable the wrapper:

If you are developing on a compatible Tegra-based tablet, NVidia provides Tegra Graphics Debugger at their website. Because SDL2 dynamically loads EGL and GLES libraries, you must follow their instructions for installing the interposer library on a rooted device. The non-rooted instructions are not compatible with applications that use SDL2 for video.

================================================================================ A note regarding the use of the “dirty rectangles” rendering technique

If your app uses a variation of the “dirty rectangles” rendering technique, where you only update a portion of the screen on each frame, you may notice a variety of visual glitches on Android, that are not present on other platforms. This is caused by SDL's use of EGL as the support system to handle OpenGL ES/ES2 contexts, in particular the use of the eglSwapBuffers function. As stated in the documentation for the function “The contents of ancillary buffers are always undefined after calling eglSwapBuffers”. Setting the EGL_SWAP_BEHAVIOR attribute of the surface to EGL_BUFFER_PRESERVED is not possible for SDL as it requires EGL 1.4, available only on the API level 17+, so the only workaround available on this platform is to redraw the entire screen each frame.